Refrigeration devices, such as, for example, refrigerators, freezers or wine storage cabinets, tend to become increasingly large to provide larger storage capacity. Regardless of their use, such refrigeration appliances have a body having an interior for receiving the objects or products to be cooled, and a door attached to the body. Refrigeration appliances always have an elastically deformable seal disposed between the body and the door to prevent warm air from entering the interior, and to prevent the cold present therein from escaping to the outside when the refrigeration appliance is closed. Due to the temperature difference between the environment and the interior of the refrigeration appliance, the warm air that has entered the interior of the refrigeration appliance after opening the door is cooled once the door is closed, causing a decrease in the volume of the air, as a result of which a vacuum develops in the interior of the refrigeration appliance and presses the door against the body with a force increased by the ambient air pressure. As a result of the door-closing force increased in this manner, the door may be impossible to open or may be openable only with substantial force, especially with increasing size of the refrigeration appliances.
In order to overcome such difficulties, various approaches have already been proposed for facilitating or performing the opening movement of the door of the refrigeration appliance, and thus help overcome the vacuum developing inside the refrigeration appliance.
For example, German Patent Application DE 10 2006 061 083 A1 describes a refrigeration appliance having a body whose interior can be closed by a door. A seal disposed between the door and the body serves in the manner described above to prevent warm air from entering the interior, and to prevent the cold present therein from escaping to the outside when the refrigeration appliance is closed. Moreover, the refrigeration appliance design presented in DE 10 2006 061 083 A1 has a control unit used for actuating an opening mechanism acting on the door. The control signal needed for this purpose is generated by at least one motion sensor which generally is capable of sensing movements of the door and of outputting in response thereto a signal to the control unit, this signal being usable for actuating the opening mechanism.
Also described is a pressure sensor that senses the pressure in the interior, which changes slightly in response to movement of the door. Such pressure variations in the interior arise, for example, when a pressure force or a pulling force is exerted on the door. This movement of the door is identified as an opening request and triggers a signal for actuating the opening mechanism.
German Patent Application DE 10 2006 061 083 A1 further describes a plunger forming part of the opening mechanism, which, in connection with a coil and a permanent magnet, serves to generate a voltage, and thus an inductive signal. In other words, different sensors are mentioned which are always used to convert a movement of the door into a control signal of the opening mechanism.
Further, DE 20 2000 011 427 U1 describes in general terms a trigger sensor having a force sensor which, according to the disclosure of the document, is used to actuate an opening mechanism.
Force sensors, in particular, have a very short measurement travel, which results in the disadvantage of having to initially adjust or zero such a sensor after installation thereof. Manufacturing and fitting tolerances between corresponding components of the refrigeration appliance can thereby be compensated for within certain limits. Such tolerances could otherwise negatively affect the measurement result. Such an adjustment operation alone is not particularly complex, but what adds to it is that the above-described vacuum developing in the interior of the refrigeration appliance may change the initial setting of the measurement travel of the sensor, requiring it to be readjusted until the selected setpoint is reached again. This is because the vacuum changes in response to varying environmental conditions, or because the adjustment of the door joints changes due to wear. Consequently, in the constructions known heretofore, the arising tolerance deviations lead to inaccuracies in the acquisition of measurement values, and also in the subsequent signal processing, which in turn may result in delayed or premature response of the opening mechanism.